﻿package com.calefk.util {
        
        import flash.display.BitmapData;
        import flash.display.BlendMode;
        import flash.display.DisplayObject;
        import flash.display.Sprite;
        
        import flash.geom.ColorTransform;
        import flash.geom.Matrix;
        import flash.geom.Point;
        import flash.geom.Rectangle;
        
        public class PixelPerfect {
 
			public static function complexHitTestObject( target1:DisplayObject, 
					target2:DisplayObject,  accurracy:Number = 1 ):Boolean{
				return complexIntersectionRectangle( target1, target2, accurracy ).width != 0;
			}
			
			public static function intersectionRectangle( target1:DisplayObject, 
				target2:DisplayObject ):Rectangle {
				// If either of the items don't have a reference to stage, then they are not in a display list
				// or if a simple hitTestObject is false, they cannot be intersecting.
				if( !target1.root || !target2.root || !target1.hitTestObject( target2 ) ) return new Rectangle();
				
				// Get the bounds of each DisplayObject.
				var bounds1:Rectangle = target1.getBounds( target1.root );
				var bounds2:Rectangle = target2.getBounds( target2.root );
				
				// Determine test area boundaries.
				var intersection:Rectangle = new Rectangle();
				intersection.x   = Math.max( bounds1.x, bounds2.x );
				intersection.y    = Math.max( bounds1.y, bounds2.y );
				intersection.width      = Math.min( ( bounds1.x + bounds1.width ) - intersection.x, ( bounds2.x + bounds2.width ) - intersection.x );
				intersection.height = Math.min( ( bounds1.y + bounds1.height ) - intersection.y, ( bounds2.y + bounds2.height ) - intersection.y );
		
				return intersection;
			}
			
			public static function complexIntersectionRectangle( target1:DisplayObject, target2:DisplayObject,
				accurracy:Number = 1 ):Rectangle {           
					
				if( accurracy <= 0 ) throw new Error( "ArgumentError: Error #5001: Invalid value for accurracy", 5001 );
				
				// If a simple hitTestObject is false, they cannot be intersecting.
				if( !target1.hitTestObject( target2 ) ) return new Rectangle();
				
				var hitRectangle:Rectangle = intersectionRectangle( target1, target2 );
				// If their boundaries are no interesecting, they cannot be intersecting.
				if( hitRectangle.width * accurracy <1 || hitRectangle.height * accurracy <1 ) return new Rectangle();
				
				var bitmapData:BitmapData = new BitmapData( hitRectangle.width * accurracy, hitRectangle.height * accurracy, false, 0x000000 ); 

				// Draw the first target.
				bitmapData.draw( target1, PixelPerfect.getDrawMatrix( target1, hitRectangle, accurracy ), new ColorTransform( 1, 1, 1, 1, 255, -255, -255, 255 ) );
				// Overlay the second target.
				bitmapData.draw( target2, PixelPerfect.getDrawMatrix( target2, hitRectangle, accurracy ), new ColorTransform( 1, 1, 1, 1, 255, 255, 255, 255 ), BlendMode.DIFFERENCE );
				
				// Find the intersection.
				var intersection:Rectangle = bitmapData.getColorBoundsRect( 0xFFFFFFFF,0xFF00FFFF );
				
				bitmapData.dispose();
				
				// Alter width and positions to compensate for accurracy
				if( accurracy != 1 )
				{
						intersection.x /= accurracy;
						intersection.y /= accurracy;
						intersection.width /= accurracy;
						intersection.height /= accurracy;
				}
				
				intersection.x += hitRectangle.x;
				intersection.y += hitRectangle.y;
				
				return intersection;
			}
			
			protected static function getDrawMatrix( target:DisplayObject, hitRectangle:Rectangle, accurracy:Number ):Matrix{
				var localToGlobal:Point;
				var matrix:Matrix;
				
				var rootConcatenatedMatrix:Matrix = target.root.transform.concatenatedMatrix;
				
				localToGlobal = target.localToGlobal( new Point() );
				matrix = target.transform.concatenatedMatrix;
				matrix.tx = localToGlobal.x - hitRectangle.x;
				matrix.ty = localToGlobal.y - hitRectangle.y;
				
				matrix.a = matrix.a / rootConcatenatedMatrix.a;
				matrix.d = matrix.d / rootConcatenatedMatrix.d;
				if( accurracy != 1 ) matrix.scale( accurracy, accurracy );
				return matrix;
			}
        }
} 